High tension electric cable



Sept. 11, 1934. K. sc g 1,973,111

HIGH TENSION ELECTRIC CABLE Filed Feb. 25, 1951 PATENT or?! lfllGfl TENSION ELECTRIC CABLE Karl Schlecker, lBerlin-Grunewald, Germany, assignor to Siemens-Schuckertwerke Aktiengeseilschaft, Berlin-Siemensstadt, Germany, a corporation of Germany Application February 25,

1931, Sei-ial No. 518,299

in Germany March 3, 930

lClaim.

This invention relatesto high tension electric cables and has for its object to maintain a safeiactory impregnation of the cables from the time they are manufactured until they are laid.

Hitherto it has generally been customary to ship and lay oil filled high tension cable lengths provided with longitudinal oil channels or cavities inside the cable, without their oil fillings, the filling being injected only after the cable length is laid. :l'his requires evacuation of the cables and further makes it necessary to carry out operations on the cable line which are of a rather troublesome character in order to eiiect the impregnation with oil in a satisfactory manner. In order to avoid this it has already been proposed to impregnate the cables at the factory by completely filling them with oil whereupon, in order to avoid the escape of oil and to prevent the iormation of hollow spaces in the cable, one end of the cable is provided with an oil reservoir which serves to keep the cable in a thoroughly impregnated condition over its whole length and is also of use for keeping the oil under a greater pressure than the pressure of the atmosphere. The other end of the cable is in the case of this arrangement closed in a pressure proof and oil tight manner by means of a suitable cap. The use of a separate vessel to serve as a reservoir is however subject to the disadvantage that for shipping such a cable specially prepared drums are necessary, whilst the oil reservoir requires a considerable amount of space. V

The present invention has for its object to avoid the disadvantages previously mentioned and for this purpose according to the invention when pressing the lead sheath on to the cable the said lead sheath is made longer than the core of the sents a longitudinal section through a cable end,

i indicates the end of the insulated cable conductors, and 2 the lead sheath, extending tor a suitable length beyond the cable end 1. within this extension are placed a number, of gas-filled pressure compensating chambers 4, provided with corrugated end walls, as shown. The gas, for ce air,inthese' maybe at er above atmospheric pressure. These chambers are surrounded by the oil 5 contained in the extension,- which communicates with the oil in the cable proper. The end of the sheath is clwed by a cap 6 which is soldered to the sheath at 7.

In this manner the cable is maintained always filled with oil and the lead sheath is kept closed in a pressure proof and oil tight manner, whilst upon changes in temperature, that is to say upon expansion or contraction of the oil, the compensating chambers are compressed or expanded respectively, and thus keep the cable always completely filled with oil.

I claim as my invention:

Means for maintaining a high tension electric cable length, having insulated conductors and a surrounding lead sheath, continuously completely impregnated with insulating liquid within the sheath, irom the time of completing the cable manufacture until it is laid, said means comprising at least at one end of the manufactured cable length an extension of the cable sheath for a suitable length beyond the cable conductors,

said extension being closed at its outer end, and

a plurality of corrugated compensating chambers surrounded by the cable liquid in said extension, and containing gas of at least atmospheric pressure, whereby the gas in said chambers, following the expansion and contraction of the cable liquid, maintains the cable completely filled with oil.

KARL SC.

Elm 

